The primary objective of our research remains that of acquiring a knowledge of the mechanism of the UDP-glucose dehydrogenase reaction, and its biological regulation. Such knowledge could be of fundamental importance in the treatment of diseases, such as neonatal jaundice, which arise from the failure of conjugation of toxic substances via UDP-glucuronic acid, the reaction product. Our studies on the mechanism of the reaction will continue to use pure UDP-glucose dehydrogenase from beef liver. Further insight into the reaction mechanism will be sought by continuing the study of the various isotope exchange reactions which the enzyme can undergo and the effect of various inhibitors on these exchange reactions, as compared to the forward reaction. We shall also continue our measurements of the binding of labeled substrates and products, with the aid of radioactively labeled nucleotides. The binding of the natural inhibitor, UDP-xylose, will be examined in similar fashion, and the effects of various combinations of effectors will be measured. Further attempts will be made to stabilize the enzyme's activity by covalent attachment to an insoluble matrix.